Suspension system control method, device and vehicle

Abstract

The present invention provides a suspension system control method, device and vehicle. The suspension system control method of the present invention relates to the field of vehicle suspension control technology. The method includes obtaining the vehicle speed and the height between each wheel and the vehicle body, calculating the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body, determining the current road condition according to the vehicle speed and the longitudinal acceleration change frequency, and controlling the height of each air spring in the suspension system to reach a preset height when the current road condition is a preset road condition. The suspension system control method of the present invention can control the height of the air spring according to the vehicle speed and the height between the wheel and the vehicle body, thereby improving the driving stability of the vehicle and the comfort of the passengers, and at the same time, can also improve the vehicle's passability and handling performance to a certain extent.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle suspension control, and in particular to a suspension system control method. At the same time, the present invention also relates to a suspension system control device capable of implementing the suspension system control method, and a vehicle equipped with the suspension system control device. Background Art

[0002] The suspension system is an important part of the car, which connects the frame and wheels elastically and affects the various performances of the car. The suspension system of the transmission cannot meet the requirements of the comfort and handling stability of the car at the same time, and these two aspects are mutually contradictory.

[0003] For example, in order to achieve good comfort, it is necessary to greatly cushion the vibration of the car, so the traditional suspension springs must be designed to be softer. However, if the suspension springs are soft, it is easy for the car to "nod" when braking, "lift its head" when accelerating, and experience severe roll, resulting in unstable car handling.

[0004] The existing electronic suspension control system is an electronic control system based on ordinary suspension, which aims to adjust the performance of the suspension by electronic means to adapt to different road conditions, thereby improving the car's ride comfort, handling stability and passability.

[0005] However, road surface flatness is one of the main factors causing vehicle suspension vibration. However, the existing electronically controlled suspension system generally adjusts the suspension parameters based on the driver's subjective judgment of road conditions when the vehicle is traveling on different roads, which is not conducive to the air suspension to perform its best performance. Summary of the invention

[0006] In view of this, the present invention aims to provide a suspension system control method to facilitate controlling the suspension system and improve the stability and comfort of the vehicle.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A suspension system control method, comprising:

[0009] Get the vehicle speed and the height between each wheel and the vehicle body;

[0010] Calculating the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body;

[0011] determining a current road condition according to the vehicle speed and the longitudinal acceleration change frequency;

[0012] When the current road condition is the preset road condition, the height of each air spring in the suspension system is controlled to reach a preset height.

[0013] Furthermore, the method of calculating the changing frequency of the longitudinal acceleration of each wheel according to the height between each wheel and the vehicle body comprises: calculating the longitudinal acceleration of each wheel according to the height between each wheel and the vehicle body; and calculating the changing frequency of the longitudinal acceleration of each wheel according to the longitudinal acceleration of each wheel.

[0014] Furthermore, when the current road condition is a preset road condition, the height of each air spring in the suspension system is controlled to reach a preset height, including: when the current road condition is a preset road condition, the first solenoid valve and motor related to the height of the air spring are controlled to operate so that the height of each air spring in the suspension system reaches a preset height.

[0015] Furthermore, the control of the first solenoid valve and the motor related to the height of the air spring to make the height of each air spring in the suspension system reach a preset height includes: controlling the second solenoid valve to be in an open state; when the second solenoid valve is in an open state, controlling the first solenoid valve and the motor related to the height of the air spring to be in an open state to make the height of each air spring in the suspension system reach a preset height.

[0016] Furthermore, after the height of each air spring in the suspension system reaches a preset height, the method also includes: determining the current road condition of the vehicle based on the vehicle speed and the current longitudinal acceleration change frequency; and closing the second solenoid valve when the current road condition is the preset road condition.

[0017] Furthermore, determining the current road condition based on the vehicle speed and the longitudinal acceleration change frequency includes: determining the maximum longitudinal acceleration change frequency among the longitudinal acceleration change frequencies based on the longitudinal acceleration change frequency of each wheel; determining the current road condition based on the vehicle speed and the maximum longitudinal acceleration change frequency.

[0018] Furthermore, determining the current road condition based on the vehicle speed and the maximum longitudinal acceleration change frequency includes: determining the current road condition grade based on the vehicle speed and the maximum longitudinal acceleration change frequency; starting to calculate time when the current road condition grade is less than a preset road condition grade threshold; determining that the current road condition is the preset road condition and clearing the first time when the calculated first time does not reach the preset time threshold and the current road condition grade is greater than or equal to the preset road condition grade threshold; and determining that the current road condition is not the preset road condition when the calculated first time reaches the preset time threshold.

[0019] Furthermore, after the first time is cleared, the method also includes: when the current road condition level is less than the preset road condition level threshold again, recalculating the time, and when the recalculated second time reaches the preset time threshold, determining that the current road condition is not the preset road condition.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The suspension system control method described in the present invention can control the height of the air spring according to the vehicle speed and the height between the wheel and the vehicle body, thereby improving the vehicle's driving stability and passenger comfort. At the same time, it can also improve the vehicle's passability and handling performance to a certain extent.

[0022] Another object of the present invention is to provide a suspension control device, comprising:

[0023] An acquisition module is used to acquire the vehicle speed and the height between each wheel and the vehicle body in real time;

[0024] A calculation module, used for calculating the longitudinal acceleration change frequency of each of the wheels according to each of the vehicle speeds and the height between the vehicle bodies;

[0025] A determination module, used to determine the current road condition according to the vehicle speed and the longitudinal acceleration change frequency;

[0026] The control module is used to control the height of each air spring in the suspension system to reach a preset height when the current road condition is a preset road condition.

[0027] The suspension control device of the present invention has the same beneficial effects as the aforementioned suspension control method relative to the prior art, and will not be described in detail herein.

[0028] Meanwhile, another object of the present invention is to provide a vehicle provided with the suspension control device as described above.

[0029] The vehicle described in the present invention, by applying the above suspension control device, is conducive to improving the stability of vehicle operation and the comfort of vehicle riding, and can provide passengers with an excellent riding experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 is an exemplary flow chart of a suspension system control method according to Embodiment 1 of the present invention;

[0032] Figure 2is another exemplary flow chart of the suspension system control method according to the first embodiment of the present invention;

[0033] Figure 3 is another exemplary flow chart of the suspension system control method according to the first embodiment of the present invention;

[0034] Figure 4 This is a principle block diagram of the suspension system control device described in Example 1 of the present invention. Description of the drawings:

[0036] 1. Acquisition module; 2. Control module; 3. Air spring height adjustment solenoid valve; 4. Motor; 5. Air spring stiffness adjustment solenoid valve; 6. Air tank solenoid valve;

[0037] 101. Height sensor; 102. Vehicle speed sensor. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] In the description of the present invention, it should be noted that the terms "upper", "lower", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0042] Embodiment 1

[0043] The present embodiment relates to a suspension system control method, which comprehensively considers the current driving state of the vehicle, determines the road grade, and intelligently adjusts the state of the suspension system to adapt to different road conditions, thereby improving the driving stability of the vehicle and the ride comfort of the vehicle.

[0044] Based on the above design concept, an exemplary structure of the suspension system control method of this embodiment is as follows: Figure 1 The method includes the following steps S101 to S104.

[0045] S101: Obtain the vehicle speed and the height between each wheel and the vehicle body.

[0046] S102: Calculate the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body.

[0047] S103: Determine the current road condition according to the vehicle speed and the longitudinal acceleration change frequency.

[0048] S104. When the current road condition is a preset road condition, control the height of each air spring in the suspension system to reach a preset height.

[0049] As shown in step S101 above, the vehicle speed information can usually be obtained through the vehicle speed sensor 102 of the vehicle, and the vehicle speed and the height h between each wheel and the vehicle body can be obtained through the height sensor 101 installed on the vehicle.

[0050] As the signal input of the system, the accuracy of the data collected by the height sensor 101 is crucial. In this embodiment, the height sensor 101 is recommended to select a sensor using a digital signal as the data type, which has strong anti-interference ability, is easy to process and supports multiplexing.

[0051] It should be noted that, in this embodiment, height sensors 101 are respectively installed at the four wheels, which can be used to respectively monitor the height h between each wheel and the vehicle body.

[0052] The advantage of this suspension system control method is that it can intelligently adjust the suspension state according to real-time road condition information, thereby improving the vehicle's driving stability and passenger comfort. At the same time, by controlling the height of the air spring, the vehicle's passability and handling performance can also be improved to a certain extent.

[0053] For example, when the driver drives on a relatively bad road, based on the height change measured by the wheel height sensor 101, when the change frequency exceeds the limit, the air spring will increase the height to improve the body's ability to pass through potholes, and increase the air spring stiffness to improve the body stability.

[0054] As mentioned above, step S102 is executed by the following calculation module, step S103 is executed by the following determination module, and step S104 is executed by the following control module 2. The control module 2 can be, for example, an existing electronic control unit (ECU) on the vehicle. The main function of the control module 2 is that after receiving the signal from the height sensor 101, the microprocessor in the control module 2 performs real-time data processing and decision-making based on the received signal in combination with the preset program and algorithm. Based on the processed result, the control module 2 generates a corresponding control signal and transmits it to the following actuator through the output port.

[0055] As a preferred implementation, before obtaining the vehicle speed and the height between each wheel and the vehicle body, the suspension system control method of this embodiment includes initializing a suspension system control device capable of implementing the suspension system control method.

[0056] Specifically, when the vehicle is powered on, the control module 2 of the suspension system control device should be initialized. During the initialization of the control module 2, the data will be initialized and the components in the system will be inspected. If there is any abnormality, some functions will be disabled. Initialization is an important process, which involves the preparation of the control module 2 before formal operation. It can set initial parameters, verify and prepare the operating environment, reduce the subsequent maintenance workload, and improve data accuracy, thereby ensuring the stable operation of the suspension system control method.

[0057] As a preferred implementation, as in the above step S102, the longitudinal acceleration change frequency of each wheel is calculated according to the height between each wheel and the vehicle body, which specifically includes step S1021 and step S1022.

[0058] S1021. Calculate the longitudinal acceleration of each wheel according to the height between each wheel and the vehicle body.

[0059] It should be noted that the longitudinal acceleration of the wheel is calculated according to a preset longitudinal acceleration calculation formula, which is obtained by taking the second-order derivative of each height with respect to time. In other words, the longitudinal acceleration is the second-order derivative of each height with respect to time.

[0060] More specifically, according to a=dh 2 / dt 2 Formula ① is used to calculate the longitudinal acceleration of each wheel. Formula ① is the preset longitudinal acceleration calculation formula.

[0061] In formula ①, a is the longitudinal acceleration of the wheel, h is the height between the wheel and the vehicle body, and t is the time.

[0062] S1022. Calculate the longitudinal acceleration change frequency of each wheel according to the longitudinal acceleration of each wheel.

[0063] It should be noted that the longitudinal acceleration change frequency is calculated according to a preset frequency calculation formula. For example, the preset frequency calculation formula adopts a standard deviation calculation formula, a root mean square calculation formula, etc. In addition, in another exemplary embodiment, the preset frequency calculation formula can also adopt the following formula ②.

[0064] according to Calculate the frequency of change of the longitudinal acceleration of each wheel.

[0065] In formula ②, X is the frequency of change of the longitudinal acceleration of the wheel, and an is t n The longitudinal acceleration of the wheel at time .

[0066] It should be noted that a1 is the longitudinal acceleration of the wheel at time t1, a2 is the longitudinal acceleration of the wheel at time t2, a3 is the longitudinal acceleration of the wheel at time t3, and so on. n The longitudinal acceleration of the wheel at time .

[0067] Specifically, formula ② first calculates the sum of the squares of the longitudinal accelerations of each wheel and then finds the average value. The square operation ensures that all values ​​are positive and can amplify the difference in acceleration. Then the average value of the sum of the longitudinal accelerations of all wheels is calculated and then squared. The square root is taken after subtracting the two. This calculation method can be used to measure the discreteness of the longitudinal acceleration of the wheel, so the stability and consistency of the acceleration of each wheel during the vehicle's driving process can be evaluated.

[0068] In a preferred embodiment, the difference between adjacent moments is preferably a fixed value, which may be 10 mS, for example, the time difference between moment t1 and moment t2 is 10 mS, and the time difference between moment t2 and moment t3 is 10 mS, that is, t n-1 Time and t n The time difference between moments is preferably a fixed value for ease of calculation. It should be understood that the difference between adjacent moments may also be set to an indefinite value.

[0069] In addition, in the above formula ②, the value of n is preferably 100-120, that is, in the calculation process, formula 2 needs to use the longitudinal acceleration values ​​of 100-120 wheels, which is conducive to improving the accuracy of the longitudinal acceleration change frequency of each wheel. It should be understood that the value of n can also be set to other numbers, which can be less than 100, such as 80, or more than 120, such as 140. Although the more the value of n is, the more accurate the calculated longitudinal acceleration change frequency is, however, the smaller the value of n is, the shorter the time used for calculation, which is conducive to saving the overall calculation time. Therefore, considering comprehensively, it is better to set the value of n between 100-120.

[0070] The suspension system control method of this embodiment can calculate the longitudinal acceleration of the wheel by continuously monitoring the change of wheel height over time. Next, the change frequency of the longitudinal acceleration of each wheel is calculated based on the longitudinal acceleration data, which reflects the degree of unevenness of the road surface and the frequency of impact on the wheel.

[0071] Next, the calculation process of the longitudinal acceleration change frequency is described in detail. Since a car generally has four wheels, and the height sensors 101 are installed at each of the four wheels, the height h between the car body and the wheel collected mainly includes h FL 、h FR 、h RL and h RR .

[0072] Among them, h FL represents the height between the vehicle body and the wheel collected by the left front height sensor 101, in mm; h FR represents the height between the vehicle body and the wheel collected by the right front height sensor 101, in mm; h RL Represents the height between the vehicle body and the wheel collected by the left rear height sensor 101, in mm; h RR It represents the height between the vehicle body and the wheel collected by the right rear height sensor 101, in mm.

[0073] Next, the height h between the vehicle body and the wheel collected by each height sensor 101 is subjected to a second-order derivative to obtain a FL 、a FR 、a RL and a RR .

[0074] Referring to the above formula ①, the following formula is listed, a FL =d(h FL )2 / dt 2 、a FR =d(h FR )2 / dt 2 、a RL =d(h RL )2 / dt 2 、a RR =d(h RR )2 / dt 2 , we can obtain a FL 、a FR 、a RL and a RR Among them, a FL is the longitudinal acceleration of the left front wheel, in m / s 2 ; a FR is the longitudinal acceleration of the right front wheel, in m / s 2 ; aRL is the longitudinal acceleration of the left rear wheel, in m / s 2 ; a RR is the longitudinal acceleration of the right rear wheel, in m / s 2 .

[0075] Next, according to the above formula ②, the longitudinal acceleration change frequency of each wheel is obtained, which is recorded as X FL , X FR , X RL , X RR , where X FL is the longitudinal acceleration change frequency of the left front wheel, X FR is the longitudinal acceleration change frequency of the right front wheel, X RL The longitudinal acceleration change frequency of the left rear wheel, X RR Frequency of change of the longitudinal acceleration of the right rear wheel.

[0076] As a preferred embodiment, Figure 3 As shown, as in step S103 above, the current road condition is determined according to the vehicle speed and the longitudinal acceleration change frequency, specifically including:

[0077] S1031. Determine a maximum longitudinal acceleration change frequency among the longitudinal acceleration change frequencies according to the longitudinal acceleration change frequencies of the wheels.

[0078] S1032. Determine the current road condition according to the vehicle speed and the maximum longitudinal acceleration change frequency.

[0079] It should be noted that since there are four longitudinal acceleration change frequencies calculated in the previous text, in order to facilitate accurate execution of the method, in this embodiment, in step S1031, the four calculated longitudinal acceleration change frequencies are compared to find the maximum value, that is, the maximum longitudinal acceleration change frequency.

[0080] In step S1032, the vehicle speed and the maximum longitudinal acceleration change frequency are input as input parameters into a pre-established road condition grade assessment model. The current road condition grade can be determined based on the output results of the road condition grade assessment model, which will be described in detail below.

[0081] As a preferred implementation, in step S1032 above, the current road condition is determined according to the vehicle speed and the maximum longitudinal acceleration change frequency, specifically including:

[0082] S10321. Determine the current road condition level according to the vehicle speed and the maximum longitudinal acceleration change frequency.

[0083] S10322. When the current road condition level is less than a preset road condition level threshold, start calculating the time.

[0084] S10323. When the calculated first time does not reach the preset time threshold and the current road condition level is greater than or equal to the preset road condition level threshold, determine that the current road condition is the preset road condition and clear the first time; when the calculated first time reaches the preset time threshold, determine that the current road condition is not the preset road condition.

[0085] It should be noted that after step S10323, step S10324 is also included.

[0086] S10324. When the current road condition level is less than the preset road condition level threshold again, restart the time calculation, and when the recalculated second time reaches the preset time threshold, determine that the current road condition is not the preset road condition.

[0087] In step S103 of this embodiment, a road condition level assessment model can be established by combining the vehicle speed and the longitudinal acceleration change frequency. The model can classify the road condition into different road conditions, such as good road condition, relatively flat road condition and uneven road condition, according to different combinations of vehicle speed and acceleration change frequency. Each road condition corresponds to a different road condition level, and the specific description is as follows. It should be noted that the preset road condition in this embodiment is described by taking the preset road condition as an uneven road condition as an example.

[0088] It should also be noted that in step S10321, this step is to evaluate the current road condition level by analyzing the vehicle speed and the maximum longitudinal acceleration change frequency at each wheel during the vehicle's driving process. For example, if the vehicle speed is slow and the longitudinal acceleration change frequency is high, it means that the road condition is poor (such as a congested section of a city). For another example, if the vehicle speed is fast and the longitudinal acceleration change frequency is relatively stable, it means that the road condition is good (such as a highway).

[0089] In step S10322, this step mentions a preset road condition level threshold, which is used to distinguish between "good" and "bad" road conditions. For example, if the current road condition level is lower than the preset road condition level threshold (that is, the road condition is better), a time period is calculated, such as the "first time" mentioned in this embodiment. The beginning of this time period means that the vehicle is monitoring whether the road condition will continue for a period of time.

[0090] Specifically, in step S10323, if the road condition level is always less than the preset road condition level within the first time, it indicates that the road condition has improved. If the road condition level is still greater than or equal to the preset road condition level threshold within the first time, it means that the improvement in road conditions is temporary, that is, the road condition has not improved. Therefore, the calculated first time is reset to zero, and the height and stiffness of each air spring are not restored, which is conducive to maintaining vehicle comfort and stability.

[0091] If the road condition level drops below the preset road condition level threshold again, it means that the road condition has improved again, and a time period called the "second time" begins to be calculated. This time period is used to further monitor whether the road condition will remain in a good state for a longer period of time.

[0092] Whether it is the "first time" or the "second time", once they reach the preset time threshold, the system will finally determine the current road condition based on the current road condition level. This means that if the road condition continues to be poor or good for a period of time, the system will evaluate the road condition based on the performance during this period, which is conducive to improving the accuracy of the road condition evaluation results.

[0093] The suspension system control method of this embodiment evaluates the road condition level by monitoring the changes in vehicle speed and acceleration, and further confirms whether the road condition is stable by calculating the time period. This method helps to judge the current road condition more accurately, thereby improving the accuracy of the decision-making of the control module 2, thereby achieving the purpose of improving vehicle stability, controllability and passability.

[0094] As a preferred embodiment, Figure 2 As shown, as in step S104 above, when the current road condition is the preset road condition, controlling the height of each air spring in the suspension system to reach the preset height includes:

[0095] When the current road condition is the preset road condition, the first solenoid valve and the motor 4 related to the air spring height are controlled to operate so that the height of each air spring in the suspension system reaches the preset height.

[0096] Since the height of each air spring in the suspension system is crucial to the stability, handling and ride comfort of the vehicle, in this embodiment, it is necessary to obtain the current height of each air spring in real time so as to timely understand the current state of the suspension, thereby providing accurate data support for subsequent control and adjustment of the control module 2.

[0097] This step is the key to the active adjustment of the suspension system. According to the current road conditions (such as good road, relatively flat road, uneven road, etc.), the system will store the corresponding preset height, and then adjust the inflation and deflation of the air spring through the first solenoid valve and motor 4 related to the air spring height to make the height of each air spring reach the preset height. This can ensure that the vehicle can maintain good handling and ride comfort under different road conditions.

[0098] It should be noted that, in the present embodiment, the road conditions are mainly divided into three types, namely, good road, relatively flat road and uneven road. It should be understood that in addition to the three types of good road, relatively flat road and uneven road, the road conditions can also be divided into more types, and the preset height and preset stiffness corresponding to each road condition can be obtained through calibration in the calibration test and stored in the non-volatile memory of the electronic control unit.

[0099] As a preferred embodiment, when the current road condition is the preset road condition, the first solenoid valve and motor 4 related to the air spring height are controlled to operate so that the height of each air spring in the suspension system reaches the preset height, including step S1041 and step S1042.

[0100] S1041. Control the second solenoid valve to be in an open state.

[0101] Specifically, when the current road condition is the preset road condition, the working state of the second solenoid valve related to the stiffness of the air spring is obtained. When the second solenoid valve is in a closed state, the second solenoid valve is controlled to be in an open state. When the second solenoid valve is in an open state, the second solenoid valve is controlled to remain in an open state.

[0102] S1042: When the second solenoid valve is in an open state, the first solenoid valve and the motor 4 related to the air spring height are controlled to operate so that the height of each air spring in the suspension system reaches a preset height.

[0103] In step S104, when it is detected that the current road condition is a preset road condition, for example, the current road condition is an uneven road condition, and the ground clearance needs to be increased to improve the passability, or the current road condition is a good road condition and the vehicle body needs to be lowered to improve the stability, the control system will adjust each air spring in the suspension system to reach the preset height corresponding to each road condition. The height adjustment of the air spring can be achieved by changing the air pressure inside it, which is usually achieved by the following solenoid valve or compressor and other devices.

[0104] Specifically, as in step S1041 above, this step is to ensure that the working state of the electromagnetic valve related to the stiffness of the air spring, i.e., the second electromagnetic valve, is checked before adjusting the height of the air spring. Still taking the air spring as a dual-chamber air spring as an example, when the air spring stiffness adjustment electromagnetic valve 5 is in a closed state, the gas between the two chambers cannot flow between the two chambers. At this time, filling and deflating the two chambers separately is not conducive to adjusting the stiffness of the air spring to an appropriate height, and the air spring cannot exert excellent performance, which also has an important impact on the vehicle's handling and ride comfort. Before adjusting the height of each air spring, its working state is confirmed.

[0105] As mentioned above, step S1041 is to open the second solenoid valve when the second solenoid valve is in the closed state, so as to adjust the stiffness of the dual-chamber air spring, which is beneficial to adjust the height of the air spring to adapt to the current road condition level.

[0106] In step S1042 as above, while ensuring that the second solenoid valve is in the open state, the height of the air spring is then adjusted. Specifically, by controlling the action of the first solenoid valve and the motor 4, the air spring can be inflated and deflated to reach a preset height. In the process of inflating and deflation of each air spring, the gas between the dual chambers of the air spring can flow with each other, so that after the height of the air spring is adjusted to the preset height, the air spring can perform excellent performance.

[0107] When the air spring is a dual-chamber air spring, the method includes steps S1041 to S1042, and when the air spring is a single-chamber air spring, the method does not include steps S1041 to S1042. Since there is no air spring stiffness adjustment solenoid valve 5, there is no need to judge the working state of the air spring stiffness adjustment solenoid valve 5, and the height of each air spring can be directly adjusted.

[0108] It should be noted that a road condition level assessment model is pre-stored in the memory of the electronic control unit, which can be shown in Table 1, for example.

[0109] Table 1: Relationship between vehicle speed and longitudinal acceleration rate of change

[0110]

[0111] In Table 1, V is the vehicle speed in km / h, and X is the longitudinal acceleration change frequency, which is specifically the maximum value of the longitudinal acceleration change frequency obtained at the four wheels. That is, Table 1 is calculated based on X FL , X FR , X RL , X RR The maximum value of the four values ​​and the vehicle speed are compiled in a two-dimensional table, and S0 to S10 represent the road condition level of the road on which the vehicle is traveling.

[0112] It should be noted that, as shown in Table 1 above, X and the road condition level are determined based on calibration tests, and the specific values ​​in Table 1 are only an exemplary implementation. The range and scale of the vehicle speed and longitudinal acceleration change frequency can be selected according to needs, and the parameters such as data S0 and S1 in the table can be preferentially selected as a theoretical value, and then modified and optimized according to the data of the actual vehicle test, and finally the data in this table is determined.

[0113] It should also be noted that, during the evaluation process of the road condition grade evaluation model, the longitudinal acceleration change frequency is calculated based on the aforementioned steps S1021 and S1022, and the longitudinal acceleration change frequency is selected based on the maximum value of the longitudinal acceleration change frequency obtained at the four wheels. Therefore, in the suspension system control method of this embodiment, the road condition grade is also determined based on the maximum value of the longitudinal acceleration change frequency obtained at the four wheels. This is conducive to improving the accuracy of the road condition grade judgment, thereby helping to improve the control accuracy of the suspension system control method.

[0114] In addition, it should be made clear that the relationship between vehicle speed and longitudinal acceleration change frequency and road condition level is not a simple linear relationship, but is affected by multiple factors. Therefore, in practical applications, it is necessary to comprehensively consider multiple factors to evaluate road condition level. At the same time, since the road condition level evaluation standards and methods may vary in different regions, specific analysis and adjustments can be made according to local conditions in practical applications, such as dividing the road condition level into more categories.

[0115] After the calibration of the parameters in Table 1 is completed, the control module 2 can automatically find out the values ​​in the execution of the above suspension system control method according to the characteristic of linear relationship between adjacent scales. For example, under the same vehicle speed condition, the grade S corresponding to any value between 0.5 and 1.5 can be obtained according to the longitudinal acceleration change frequency, such as two adjacent scales of 0.5 and 1.5.

[0116] Control module 2 makes a judgment based on the level S obtained from table 1 and two design limits SL1 and SL2 (Note: the design limits are fixed parameters, which are reasonably set based on the S measured by the vehicle on different road surfaces. SL1 and SL2 are the preset road condition levels described below). Three areas can be divided according to the two limits, namely good road 1, relatively flat road 2, and uneven road 3.

[0117] For example, when S<SL1, the current road condition is determined to be a good road condition, and good road 1 is output; when SL1≤S<SL2, the current road condition is determined to be a relatively flat road condition, and relatively flat road 2 is output; when SL2≤S, the current road condition is determined to be an uneven road condition, and uneven road 3 is output. When the output value of the current road condition is equal to 3, it is considered that the current road condition is the preset road condition, and the height of each air spring in the suspension system needs to be controlled to reach the preset height. Generally, when the output value is equal to 3, the current air spring needs to increase the height. When the output value is less than 3, it is considered that no action is required at present, that is, do not adjust the height of each air spring in the suspension system.

[0118] It should be noted that, in the following text, the specific means of adjustment will be different depending on the type of air spring. For example, when the air spring is the dual-chamber air spring described below, if the output value is equal to 3, it is considered that the current road condition is the preset road condition, and it is necessary to control the height of each air spring in the suspension system to reach the preset height. After the height of each air spring in the suspension system reaches the preset height, the road condition level of the vehicle judged by the control module 2 is continuously obtained. When the current road condition output value is still equal to 3, the stiffness of each air spring in the suspension system can be adjusted. Generally, this is achieved by closing the air spring stiffness adjustment solenoid valve 5 described below.

[0119] It should also be noted that in this embodiment, when the current road condition output value is equal to 3, the control module 2 should immediately record the current air spring height h 当前高度 and k 当前刚度 , and store these two values ​​in the non-volatile memory (NVM) of the control module 2.

[0120] Then, the control module 2 should calculate the deviation between the current height of the air spring and the preset height, h 偏差 =h 当前高度 -h 预设高度 .

[0121] When the deviation h 偏差 Greater than the system's tolerance h 公差 When the air suspension system needs to perform an ascending action, the control module 2 should energize the air tank solenoid valve 6 of the air tank to open the air tank solenoid valve 6 so that the gas in the air tank can flow into the pipeline of the suspension system, and then turn on the motor 4 to pressurize the gas in the air tank, and then open the corresponding air spring height valve with deviation to realize inflation and improve the overall posture of the vehicle. When the deviation h 偏差 Smaller than the system tolerance h 公差 It is assumed that the air spring does not need to be adjusted.

[0122] It should also be noted that, still taking the air spring as a dual-chamber air spring as an example, after the lifting action of each air spring of the suspension system is completed, the control module 2 will determine whether the current air spring stiffness adjustment solenoid valve 5 is in a closed state.

[0123] If the current air spring stiffness adjustment solenoid valve 5 is not closed, the control module 2 should energize the air spring stiffness adjustment valve (Note: the stiffness valve is open by default when there is no current) to close it, so that the stiffness of the air spring increases. If the current air spring stiffness adjustment solenoid valve 5 is closed, it is considered that the air spring does not need to be adjusted. It should be understood that when the air spring is a single-chamber air spring, this step is not necessary.

[0124] After the stiffness and height of the air spring are adjusted, the system will still detect the rate of change of acceleration in real time to judge the level. For details, please refer to the aforementioned steps S10322 to S10324.

[0125] When the current road condition level S is less than SL1 at a certain moment, the internal counter of the control module 2 will start counting, which is counted as the first time. When the count value of the counter reaches the specified value such as the preset time threshold at the first time, it is considered that the vehicle has left the uneven road. At this time, the air spring should be adjusted back to the state before entering the uneven road. 当前高度 and k 当前刚度 , to maintain the state initially set by the passenger.

[0126] If after the counter starts counting, the calculated current road condition level S is greater than or equal to SL2 again, the control module 2 will clear the counter and stop counting until the level S is less than SL1 again. The counter starts counting again, recorded as the second time, until the specified preset time threshold is reached. If both the first time and the second time do not reach the specified preset time threshold, for example 100ms, the height and stiffness of each air spring do not need to be adjusted.

[0127] It should also be noted that after the height and stiffness of each air spring are adjusted, during the process of continuously calculating the current road condition level S, if it is considered that the vehicle has left the uneven road, the air spring stiffness adjustment valve can be opened first, and then the current road condition level S can be continuously evaluated. If it is still considered that the vehicle has left the uneven road, the air spring height adjustment valve can be adjusted again to adjust each air spring back to the state before entering the uneven road. 当前高度 and k 当前刚度 , to maintain the state initially set by the passenger.

[0128] As a preferred embodiment, after step S1042 as above, after the height of each air spring in the suspension system reaches a preset height, the control method further includes step S201 and step S202, which are all executed by the control module 2 described below.

[0129] S201. Determine the current road condition of the vehicle according to the vehicle speed and the current longitudinal acceleration change frequency.

[0130] S202: When the current road condition is the preset road condition, close the second solenoid valve related to the stiffness of the air spring.

[0131] In this embodiment, step S201 is to evaluate the current road condition level of the vehicle in real time. By monitoring the frequency of changes in vehicle speed and longitudinal acceleration, the control module 2 can determine whether the vehicle is traveling on a good road or on a complex road condition such as bumps, ups and downs or sharp turns. This evaluation is crucial for the subsequent adjustment of the parameters of each air spring in the suspension system.

[0132] As for step S202, this step is performed after adjusting the height of the air spring, and step S202 is only performed when all the air springs of the vehicle are dual-chamber air springs. Steps S201 and S103 are both used to determine the current road condition level based on the vehicle speed and the longitudinal acceleration change frequency. In this embodiment, the process of determining the current road condition level based on the vehicle speed and the longitudinal acceleration change frequency is performed in real time.

[0133] When the air spring is a dual-chamber air spring, step S102 is executed to determine the current road condition level, and then adjust the stiffness of the air spring according to the preset requirements. In this embodiment, the stiffness characteristics of the air spring can be changed by closing the second solenoid valve related to the stiffness of the air spring to adapt to different road conditions. For example, when driving on a good road condition such as a smooth road, a lower stiffness may be required to improve riding comfort; while in a complex road condition such as an uneven road condition, a higher stiffness is required to improve the handling stability of the vehicle.

[0134] It should be noted that, in addition to only controlling the opening and closing of the air spring stiffness adjusting solenoid valve 5, the type of the air spring stiffness adjusting solenoid valve 5 can also be adjusted according to the specific air spring stiffness. By adjusting the opening of the air spring stiffness adjusting solenoid valve 5, the purpose of adjusting the air spring stiffness is achieved. The preset height and preset stiffness are calibrated and obtained in the experiment, and stored in the non-volatile memory of the control module 2.

[0135] The suspension system control method of this embodiment can judge the road surface grade according to the vehicle speed and the height between the wheels and the vehicle body, and then determine the road condition and control the height and stiffness of the air spring according to the road surface grade, thereby improving the vehicle's driving stability and passenger comfort. At the same time, it also greatly improves the vehicle's passability and maneuverability on uneven roads.

[0136] At the same time, another object of the present invention is to propose a suspension control device, including an acquisition module 1, a calculation module, a determination module and a control module 2, wherein the acquisition module 1 is used to obtain the vehicle speed and the height between each wheel and the vehicle body, that is, to execute the aforementioned step S101, and the calculation module is used to calculate the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body, the determination module is used to determine the current road condition according to the vehicle speed and the longitudinal acceleration change frequency, and the control module 2 is used to control the height of each air spring in the suspension system to reach a preset height when the current road condition is a preset road condition, that is, to execute the aforementioned steps S102 to S104.

[0137] It should be noted that the acquisition module 1 may include, for example, the aforementioned height sensor 101 and vehicle speed sensor 102 , and the control module 2 may be, for example, an existing electronic control unit on the vehicle.

[0138] The suspension control device of this embodiment further includes an actuator, which specifically includes a first solenoid valve, a second solenoid valve and a motor 4. Figure 4 As shown, the control module 2 is connected to the first solenoid valve, the second solenoid valve and the motor 4 respectively.

[0139] It should be noted that air springs are generally classified according to the number of chambers, including single-chamber air springs and double-chamber air springs, wherein the single-chamber air spring has only one air cavity, which is usually a rubber airbag filled with compressed air.

[0140] The dual-chamber air spring is a high-performance shock absorber having two chambers. The stiffness and damping characteristics of the spring are changed by adjusting the gas pressure and volume in the two chambers. An air spring stiffness adjusting solenoid valve 5 is provided between the two chambers. The stiffness of the dual-chamber air spring can be adjusted by adjusting the opening and closing degree of the air spring stiffness adjusting solenoid valve 5.

[0141] Figure 4 The structure shown is described by taking the dual-chamber air springs installed at the four wheels of the vehicle as an example. At this time, the first solenoid valve in this embodiment is a solenoid valve related to the height of the air spring, which includes, for example Figure 4 The air spring height adjustment solenoid valve 3 and the air tank solenoid valve 6 in the embodiment of the present invention are provided, and the second solenoid valve is a solenoid valve related to the stiffness of the air spring, which includes, for example, Figure 4 Air spring stiffness adjustment solenoid valve 5.

[0142] Among them, the air spring height adjustment solenoid valve 3 is usually installed on the frame or frame crossbeam. It is responsible for controlling the gas in and out of the air spring, thereby adjusting the air pressure in the air spring and adjusting the height of the air spring, thereby achieving adjustment of the vehicle height and posture.

[0143] The gas tank is equivalent to the air storage medium in the suspension system. The gas tank solenoid valve 6 is responsible for the entry and exit of the gas in the gas tank. When the gas tank solenoid valve 6 is opened, the gas in the gas tank can flow to the air spring, and when the gas tank solenoid valve 6 is closed, the gas in the gas tank cannot flow to the air spring.

[0144] The motor 4 is a key auxiliary component of the gas tank, which is used to increase the pressure in the gas tank. For example, the motor 4 can be an existing air compressor.

[0145] The air spring stiffness regulating solenoid valve 5 can mainly regulate the air pressure in the two chambers of the air spring. By controlling the opening and closing state of the air spring stiffness regulating solenoid valve 5, the stiffness of the dual-chamber air spring can be changed, thereby adjusting the comfort and stability of the vehicle.

[0146] It should be understood that, in addition to installing dual-chamber air springs at the four wheels of the vehicle, single-chamber air springs may also be installed at the four wheels respectively. In this case, only the first solenoid valve is provided in this embodiment, and the second solenoid valve is not provided.

[0147] It should also be noted that the control module 2 of this embodiment can execute the suspension system control method of this embodiment, which can specifically be an existing vehicle sensor on the vehicle. Specifically, the vehicle controller includes one or more processors and one or more memories. The processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor can be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state.

[0148] In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content that needs to be displayed on the display screen. In some embodiments, the processor may also include an AI (Artificial Intelligence) processor, which is used to process computing operations related to machine learning. The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory, and non-volatile memory, such as one or more disk storage devices, flash memory storage devices.

[0149] In some embodiments, the non-transitory computer-readable storage medium in the memory is used to store at least one computer program, and the at least one computer program is used to be executed by the processor to implement the suspension system control method of this embodiment. It can be understood by those skilled in the art that the vehicle controller may include more or fewer components, or combine certain components, or adopt different component arrangements in addition to a memory and a processor.

[0150] The suspension control device of the present invention has the same beneficial effects as the aforementioned suspension control method relative to the prior art, and will not be described in detail herein.

[0151] Embodiment 2

[0152] This embodiment relates to a vehicle, on which the suspension control device as described in the first embodiment is provided.

[0153] The vehicle of this embodiment, by applying the above suspension control device, is conducive to improving the stability of vehicle operation and the comfort of vehicle ride, and can provide passengers with an excellent riding experience.

[0154] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A suspension system control method, characterized in that: The method comprises: Get the vehicle speed and the height between each wheel and the vehicle body; Calculating the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body; determining a current road condition according to the vehicle speed and the longitudinal acceleration change frequency; When the current road condition is the preset road condition, the height of each air spring in the suspension system is controlled to reach a preset height.

2. The suspension system control method according to claim 1, characterized in that: The calculating the longitudinal acceleration change frequency of each wheel according to the height between each wheel and the vehicle body comprises: Calculating the longitudinal acceleration of each wheel according to the height between each wheel and the vehicle body; The longitudinal acceleration change frequency of each wheel is calculated according to the longitudinal acceleration of each wheel.

3. The suspension system control method according to claim 1, characterized in that: When the current road condition is the preset road condition, controlling the height of each air spring in the suspension system to reach a preset height includes: When the current road condition is the preset road condition, the first electromagnetic valve and the motor (4) related to the height of the air spring are controlled to operate so that the height of each air spring in the suspension system reaches the preset height.

4. The suspension system control method according to claim 3, characterized in that: The method controls the first electromagnetic valve and the motor (4) related to the height of the air spring to operate so that the height of each air spring in the suspension system reaches a preset height, including: Controlling the second solenoid valve to be in an open state; When the second solenoid valve is in an open state, the first solenoid valve and the motor (4) related to the height of the air spring are controlled to operate so that the height of each air spring in the suspension system reaches a preset height.

5. The suspension system control method according to claim 4, characterized in that: After the height of each of the air springs in the suspension system reaches a preset height, the method further includes: Determining a current road condition on which the vehicle is traveling according to the vehicle speed and the current longitudinal acceleration change frequency; When the current road condition is the preset road condition, the second solenoid valve is closed.

6. The suspension system control method according to any one of claims 1 to 5, characterized in that: Determining the current road condition according to the vehicle speed and the longitudinal acceleration change frequency includes: Determining a maximum longitudinal acceleration change frequency among the longitudinal acceleration change frequencies according to the longitudinal acceleration change frequencies of the wheels; The current road condition is determined according to the vehicle speed and the maximum longitudinal acceleration change frequency.

7. The suspension system control method according to claim 6, characterized in that: The determining the current road condition according to the vehicle speed and the maximum longitudinal acceleration change frequency includes: Determining a current road condition grade according to the vehicle speed and the maximum longitudinal acceleration change frequency; When the current road condition level is less than the preset road condition level threshold, the time starts to be calculated; When the calculated first time does not reach the preset time threshold and the current road condition level is greater than or equal to the preset road condition level threshold, the current road condition is determined to be the preset road condition and the first time is cleared; when the calculated first time reaches the preset time threshold, it is determined that the current road condition is not the preset road condition.

8. The suspension system control method according to claim 7, characterized in that: After clearing the first time, the method further includes: When the current road condition level is again less than the preset road condition level threshold, the time is recalculated, and when the recalculated second time reaches the preset time threshold, it is determined that the current road condition is not the preset road condition.

9. A suspension control device, characterized in that: include: An acquisition module (1) is used to acquire the vehicle speed and the height between each wheel and the vehicle body in real time; A calculation module, used for calculating the longitudinal acceleration change frequency of each of the wheels according to each of the vehicle speeds and the height between the vehicle bodies; A determination module, used to determine the current road condition according to the vehicle speed and the longitudinal acceleration change frequency; The control module (2) is used to control the height of each air spring in the suspension system to reach a preset height when the current road condition is a preset road condition.

10. A vehicle, characterized in that: The vehicle is provided with the suspension control device according to claim 9.

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